Previous replies are correct. You do not have the drivers loaded. The APX radios use IP addressing so they appear as a networked device. If you have a firewall you will have to grant permission for this device.

1. Install CPS. It will install the drivers.
2. Attach cable to computer, radio to cable, turn radio on. The first time yo do this the computer will prompt with New Hardware Found-so tell it to automatically install the drivers. Wait for the for the Device Ready to Use Message.
3. Launch CPS. Make sure under Device/Communication Method, USB is selected.
4. Click Read a radio-USB. Wait a bit it takes some time before it finishes and verifies the codeplug.

Latest CPS is R04.00.01

If you have programmed Motorola radios before then your in for an awakening. If you haven't programmed Motorola radios before then your in for a rude awakening.